Investigation of single-layer/multilayer self-assembled InAs quantum dots on GaAs{sub 1-x}Sb{sub x}/GaAs composite substrates

Journal Article · Mon Sep 07 00:00:00 EDT 2015 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4929639· OSTI ID:22494827

Tang, Dinghao ^[1]; Kim, Yeongho; Faleev, Nikolai; Honsberg, Christiana B. ^[2]; Smith, David J. ^[3]

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1. School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, Arizona 85287 (United States)
2. School of Electrical, Computer and Energy Engineering, Arizona State University, Tempe, Arizona 85287 (United States)
3. Department of Physics, Arizona State University, Tempe, Arizona 85287 (United States)

The structure-performance properties of single-layered and multi-layered InAs/GaAs{sub 1−x}Sb{sub x} quantum dot (QD) system, grown by molecular beam epitaxy on GaAs (001) substrates, have been investigated as a function of Sb concentration. Electron microscopy observations showed no significant crystalline defects for the single-layered InAs QDs (Sb 20%). X-ray diffraction analysis revealed that the increase of Sb concentration from 7.3% to 10.2% for the multi-layered QDs increased the strain relaxation from 0% to ∼23% and the dislocation density of GaAsSb layers went up to 3.6 × 10{sup 9 }cm{sup −2}. The peak energy of QD luminescence was red-shifted with increasing Sb concentration due to reduced strain inside QDs. Moreover, the carrier lifetime of the QDs was highly improved from 1.7 to 36.7 ns due to weak hole confinement as the Sb concentration was increased from 7.3% to 10.2%. These structures should be highly promising as the basis for photovoltaic solar-cell applications. Finally, the increased Sb concentration increased the thermal activation energy of electrons confined in the QDs from 163.7 to 206.8 meV, which was indicative of the improved thermal stability with Sb concentration.

• OSTI ID: 22494827
• Journal Information: Journal of Applied Physics, Vol. 118, Issue 9; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ABUNDANCE
ACTIVATION ENERGY
ANTIMONY
CARRIER LIFETIME
DISLOCATIONS
ELECTRON MICROSCOPY
ELECTRONS
GALLIUM ARSENIDES
HOLES
INDIUM ARSENIDES
LUMINESCENCE
MEV RANGE
MOLECULAR BEAM EPITAXY
PHOTOVOLTAIC EFFECT
QUANTUM DOTS
RED SHIFT
RELAXATION
SOLAR CELLS
SUBSTRATES
X-RAY DIFFRACTION